Multitasking abilities are vital for conducting flight missions. Traditional theories of multitasking suggest that cognitive resources represent a determining factor of said performance. The current study takes a different approach by investigating how the stability-flexibility-dilemma of cognitive control influences multitasking performance in a simulated flight environment. Besides, we investigate how this dilemma interacts with performance and workload when an additional partner is present. For this purpose, 42 participants were recruited to perform the open-source version of the Multi-Attribute Task Battery (openMATB) in two different experimental conditions. Initially, participants performed the openMATB alone either in a stable or flexible control mode, which was manipulated via a gamification method (assessment 1). Afterward, two participants performed the openMATB together as a team -- again in a stable and flexible control mode (assessment 2). Results indicate that the stability-flexibility-dilemma affected the participants' individual task performance. Furthermore, the participants' performance improved in teams. However, this effect depended on subtask characteristics and the operated cognitive control mode. Implications for the design of adaptive assistance systems and suggestions for future research are discussed.